450hp Volvo S60 Drive-E Concept: Driven

Looks like a minicab, goes like a jet-engined dragster - meet Volvo's triple boost specific output champion

Jealousy is a powerful emotional force for car companies, like the rest of us. Especially, it seems clear, when it comes to specific output.

It's two years since Mercedes introduced the A45 AMG, with 180hp per litre of swept capacity. Then, last year, Volkswagen raised the bar by showing - although not yet producing - a 400hp version of the 'EA888' turbocharged 2.0 litre four-pot. At which point, Volvo's senior powertrain engineers clearly thought "we'll have a bit of that."

Yes, this looks complicated

Bringing us to Gothenburg, and the short, cresty track at the Volvo Experience Centre next to the company's vast Torslanda factory. We're here to drive a car that, apart from its decal-covered flanks and a natty set of Polestar alloys, looks like a rep-spec S60 saloon. Only this one is fitted with a 450hp 2.0-litre four-cylinder engine. That's 225hp/ litre.

Sorry, how much?
This mad franken-S60 exists for several reason. Firstly, as a rolling testbed for an ultra-powerful version of Volvo's modular four-cylinder engine, with two turbochargers and an electric supercharger working together to produce that eyebrow-stretching output. But it's also a bit of corporate willy waving, welcome proof that independent Volvo has both the appetite and the ability to take on the bigger boys. And although the official line is that this prototype is nothing more than a technology demonstrator, we've also got an impressive number of the company's senior engineers on hand to drop broad hints that something very similar might feature in the company's medium-term plans as a performance halo.

Why? Because Volvo is well on its way to phasing out all of its bigger engines. The V8 was quietly dropped a couple of years ago, and both five- and six-cylinder powerplants are close to retirement. By the end of 2017 every Volvo will have four (or fewer) cylinders, with a maximum capacity of 2.0 litres, from the boggo V40 to the range-topping 'T8' XC90. And every engine will be based on the same Drive-E architecture, which has enough commonality to allow petrol and diesel versions and motors with vastly different outputs to share common components.

Just in case you weren't aware!

80s chocolate bar
Bringing us to boost, and lots of it. Because while Volvo plans to increase the performance of its top-flight models with hybrid assistance, the company still sees a place for a high-output conventional engine. Cough, Polestar, cough. And hence this intriguing 'triple boost' version.

The S60 uses two Borg-Warner turbos plumbed in parallel, with one fed by the exhaust gases from cylinders one and four and the other spun by numbers two and three. The role of the 'leccy supercharger - which requires 48 volts and a very trick super capacitor power pack in the boot - is to help spool up the turbos to reduce lag sitting upstream of them on the induction side. At higher engine speeds the supercharger is bypassed and the turbos are left to work by themselves, each delivering up to 3.5bar of boost. To keep up, the fuelling side needs new high-flow injectors and twin fuel pumps. Peak power is claimed to be 450hp at 6,500rpm, accompanied by 369lb ft of torque which peaks at 6,000rpm, but with over 80 per cent available from just 2,000rpm.

To put that into some kind of crazy-mad Swedish perspective, that's almost exactly the same specific output that the Koenigsegg One:1 delivers (227hp/ litre) when forced to run on unleaded rather than its preferred brew of E85.

And here, very simply, is how it works

Swedish meat. Balls.
Driving impressions are going to be harvested from a few laps of the Torslanda track. A sighting lap, in what feels like a factory fresh Volvo 164 straight from the company's museum, reveals the circuit is pretty much all corner, with a series of lo-o-o-ng turns over crests stuck together by some very short straights. Oh, and the prototype is running on winter-spec Michelin Pilot Alpins, and both air and track temperatures are hovering around a bracing zero degrees.

The S60 is definitely a hard-working prototype rather than a pampered show star. The dashboard is full of warning lights, including one that tells us not to expect any help from the stability control, and there are several cool isolator switches including an emergency cut-off that looks like it could launch a Trident missile. The car has been circulating before we get our turn, and from the outside it's definitely loud, with a rorty, sometimes flatulent soundtrack that brings the Mercedes A45 to mind. Inside the cabin it feels barely quieter, with booming harmonics and low-frequency hum from the fruity exhaust.

But the new engine certainly delivers. Despite the promise of the supercharger it's not lag free; below 2,000rpm there's a distinct pause between pressing the throttle and feeling the boost arrive. But, once up and running, it pulls as hard as the numbers lead you to expect, and without any of the sensation of top-end tightness you often get from modern turbos. The track's longest straight is barely enough to see an indicated 130km/h - in blatant disregard to the posted 70km/h speed limit - but the rate at which the triple boost is still accelerating suggests that, if it found itself on that mythical derestricted Autobahn so popular with road testers, it would reach its 250km/h considerably faster than any other Volvo.

As prototypes go it promises a lot

The prototype's gearbox is the weak link in the powertrain, Volvo's eight-speed auto struggling to keep up when either left to its own devices or under manual direction. And while we're being critical, although Polestar has apparently tweaked the prototype's chassis, it's been with limited effect.

On the Torslanda track it felt very much like a generic fast Volvo, with little sensation through the low geared steering and a predictable tendency to understeer in the long, slippery corners. It uses the same Haldex-based four-wheel drive system as other fast S60s, with this clearly set up to maximise outright grip rather than to do anything proactive to help you tighten a widening line. Or, in other words, a bit soulless, but very effective at going fast.

But it's the engine that's brought us here, there's plenty of time to tweak the gearbox and chassis of any production version - and the droning exhaust note. And, on first impressions, Volvo has pulled off a very neat trick. Any engine with this sort of specific power output should be boosty and laggy and borderline undriveable; yet the prototype feels as tractable and responsive as the old T6 or T5, just about twice as fast.

Forget the downsizing and the hybrids, Volvo might have a performance future after all.

VOLVO S60 DRIVE-E HIGH PERFORMANCE CONCEPT
Engine: 1,969cc, twin-turbo four-cyl with electric supercharger
Transmission: 8-speed auto, four-wheel drive
Power (hp): 450@6,500rpm
Torque (lb ft): 369@6,000rpm
0-62mph: N/A (current T6 5.9 seconds)
Top speed: 155mph (limited)
Weight: N/A (current T6 operates with a 'serving weight' of 1,570 kg - 1,766 kg)
MPG: N/A (current T6 44.1mpg)
CO2: N/A (current T6 149g/km)
Price: Only a prototype for now...